The field of art to which this invention relates includes overhead safety guards for industrial vehicles.
It is standard practice to equip industrial lift trucks and other industrial vehicles with overhead guards to protect the operator in case a load accidentally falls from a point above. The guard, of course, must extend over the operator's compartment at a height sufficient to provide adequate head clearance for the operator, while at the same time being of such a low overall height as to provide access to relatively low overhead areas, such as operation in and out of freight cars, and the like. Heretofore the overhead grille construction of inverted U-shaped four-legged guards for lift trucks has been of one of a few basic designs, viz., (1) a criss-cross design of bars and rods in which the bars ordinarily run longitudinally of the guard and are butt welded at the front and rear rails thereof with a plurality of transverse rods extending through or welded to the bars and/or to the side rails of the guard, such as is shown in the canopy design of U.S. No. 3,289,871; or (2) a similar bar and rod grille design as referred to in item (1), but also having a curved metal plate to extend the grille to the rear to provide adequate operator protection in trucks of certain designs, such as is shown in U.S. Pat. No. 3,679,256; or (3) relatively large transversely extending spaced bars which are butt welded at the ends to the side rails of the bridge structure, such as shown in U.S. Pat. No. 3,472,550; or (4) a reinforced perforated metal plate which covers the area between the rails of the bridge and which is ordinarily welded thereto, such as shown in Patent 2,911,232. Variations of these four design types have appeared from time to time, but together they tend to summarize the background prior art. SUMMARY
This invention provides improvements in driver's overhead guards for industrial vehicles wherein spaced, parallel longitudinally extending bars form with a four-sided support an overhead protective bridge structure, the bars being preferably press fitted in transversely spaced notches formed in front and rear hollow multi-sided bridge members. The combination comprising by bridge structure provides a number of advantages over prior overhead guard structures including high rigidity and resistance to torsional forces combined with reduced weight, improved visibility through the bridge structure, improved appearance and faster assembly time partly as a result of minimizing the number of weldments, lower cost, a reduction in noise in the operator's compartment in relation to certain prior bridge constructions and more readily controlled quality in part resulting from improvements in the method of manufacture.
It is a primary object of my invention to provide a much improved guard bridge structure.